Implement webfinger discovery

includes/server/actors.php

@@ -1,8 +1,6 @@
 <?php
 namespace actors;
 
-define( 'PTEROTYPE_BLOG_ACTOR_SLUG', '-blog' );
-
 function get_actor( $id ) {
     global $wpdb;
     $row = $wpdb->get_row( $wpdb->prepare(
@@ -69,7 +67,7 @@ function get_blog_actor() {
         ),
         'name' => get_bloginfo( 'name' ),
         // TODO in the future, make this configurable, both here and in the Webfinger handler
-        'preferredUsername' => 'blog',
+        'preferredUsername' => PTEROTYPE_BLOG_ACTOR_USERNAME,
         'summary' => get_bloginfo( 'description' ),
         'url' => network_site_url( '/' ),
     );

includes/server/webfinger.php

@@ -1,6 +1,8 @@
 <?php
 namespace webfinger;
 
+require_once plugin_dir_path( __FILE__ ) . 'actors.php';
+
 function generate_rewrite_rules( $wp_rewrite ) {
     $dot_well_known = array(
         '.well-known/webfinger' => 'index.php?well-known=webfinger'
@@ -19,11 +21,55 @@ function parse_request( $req ) {
 
 function query_vars( $query_vars ) {
     $query_vars[] = 'well-known';
+    $query_vars[] = 'resource';
     return $query_vars;
 }
 
 function handle( $query ) {
-    echo var_dump( $query );
+    if ( ! array_key_exists( 'resource', $query ) ) {
+        header( 'HTTP/1.1 400 Bad Request', true, 400 );
+        echo __( 'Expected a "resource" parameter', 'pterotype' );
+        exit;
+    } 
+    $resource = $query['resource'];
+    $matches = array();
+    $matched = preg_match( '/^acct:([^@]+)@(.+)$/', $resource, $matches );
+    if ( ! $matched ) {
+        header( 'HTTP/1.1 404 Not Found', true, 404 );
+        echo __( 'Resource not found', 'pterotype' );
+        exit;
+    }
+    $account_name = $matches[1];
+    $account_host = $matches[2];
+    if ( $account_host !== $_SERVER['HTTP_HOST'] ) {
+        header( 'HTTP/1.1 404 Not Found', true, 404 );
+        echo __( 'Resource not found', 'pterotype' );
+        exit;
+    }
+    if ( $account_name === PTEROTYPE_BLOG_ACTOR_USERNAME ) {
+        $account_name = PTEROTYPE_BLOG_ACTOR_SLUG;
+    }
+    get_webfinger_json( $resource, $account_name );
+    exit;
+}
+
+function get_webfinger_json( $resource, $actor_slug ) {
+    $actor = \actors\get_actor_by_slug( $actor_slug );
+    if ( is_wp_error( $actor ) ) {
+        header( 'HTTP/1.1 404 Not Found', true, 404 );
+        echo __( 'Resource not found', 'pterotype' );
+        exit;
+    }
+    $json = array(
+        'subject' => $resource,
+        'links' => array(
+            'rel' => 'self',
+            'type' => 'application/activity+json',
+            'href' => $actor['id'],
+        ),
+    );
+    header( 'Content-Type: application/jrd+json', true );
+    echo wp_json_encode( $json );
     exit;
 }
 ?>

pterotype.php

@@ -5,6 +5,8 @@ Plugin Name: Pterotype
 require_once plugin_dir_path( __FILE__ ) . 'includes/init.php';
 
 define( 'PTEROTYPE_VERSION', '0.0.4' );
+define( 'PTEROTYPE_BLOG_ACTOR_SLUG', '-blog' );
+define( 'PTEROTYPE_BLOG_ACTOR_USERNAME', 'blog' );
 
 function pterotype_init() {
     do_action( 'pterotype_init' );